ERR (Electronic Return Receipt) is an official United States Postal Service® (USPS) document designed to be equivalent to the hardcopy 'green card' Return Receipt.
It provides the following information:

• Name of the Recipient
• Time when article is delivered
• Signature (image) of the Recipient
• Address where the item is delivered, and
• Date when the article gets delivered.

ERR is combined with certain classes and categories of mails, which are as follow:

• First-Class Mail®
• Priority Mail®

ERR Batch supports two types of Shipment Document format:

• Shipping Label
• Coversheet

This API "Create Bulk Shipments with ERR" operation requires the following information:

• Recipient (Single or Multiple)
• Carrier - USPS
• Service
• Parcel Type, and
• Special Service.

The ERR API works at two levels: Shipment level and Root level. Root level is marked as Default, where multiple shipments are processed and entities are common for all shipments. While at Shipment level, entities might differ.
User can either define values for CarrierAccountID, ParcelType, ServiceID, and SpecialService respectively at the Root level for all shipments, or mention the values at Shipment level, i.e., for individual shipment(s).
If user does not provide values for the above-mentioned fields combinedly at Shipment level, then the default values for these fields provided at Root level will be considered. While, if user provides these values combinedly at Shipment Level for individual shipment(s), it will override the values defined at Root level.

Condition: The fields CarrierAccountID, ParcelType, ServiceID are treated as a combination, and values against each field must be provided if user selects Shipment level. In case any of these field(s) out of the mentioned combination is/are missing, it will return validation error.